Various types of viewing scopes, such as endoscopes, are generally well known in the art. Generally, an endoscope is a medical device for insertion into a body passageway or cavity that enables an operator to view and/or perform certain surgical procedures at a site inside a patient's body. As is known, endoscopes may be either rigid or flexible, and generally include a long tubular member equipped with, for example, some type of system for transmitting images to the user, and in some cases, a working channel for a surgical instrument.
More specifically, the scope itself generally comprises an elongated shaft having a distal end and a proximal end, and at least one internal passageway extending between the distal end and the proximal end. Optics are disposed at the distal end of the shaft and extend through an internal passageway of the shaft, such that the optics can capture an image of a selected region located near the distal end of the shaft and convey that image to the proximal end of the shaft. An image sensor, such as a camera, is disposed adjacent to the proximal end of the shaft, such that the image obtained and transmitted by the optics can be conveyed to a display device to be viewed by a physician.
One problem with such systems, however, is that, as a surgeon manipulates the scope and camera, the camera faithfully relates what it sees, with its own upright axis displayed as the upright axis of the image on the display, which often results in rotation of the images being viewed. As the image rotates, the surgeon loses track of which direction is actually up inside the endoscopic cavity. This disorientation is one of the major challenges in endoscopy, and, at times, has resulted in severe mistake such as the snipping of optical nerves that, during the procedure, were believed to be a different part of the anatomy. Accordingly, the surgeon must continuously try to correlate his own mental picture of the anatomy with the endoscopic picture of the display. Indeed, the need to be sure of which direction is up is so important that it has become common for surgeons to observe the flow direction of fluid droplets on the endoscope cover window or search for pooling blood in order to get a sense of direction inside the cavity. Additionally, besides the importance of being able to distinguish between anatomical features that look similar, it is also important to be sure of the up direction in order to help understand the position of the scope relative to the surrounding anatomy.
Accordingly, a number of systems have been proposed to maintain the proper upright, gravity-leveled orientation of the endoscopic images irrespective of how the endoscope is being manipulated. Examples, of such systems are described in U.S. Pat. No. 5,307,804 to Bonnet, U.S. Pat. No. 5,899,851 to Koninckx, U.S. Pat. No. 6,097,423 to Mattsson-Boze, et al., U.S. Pat. No. 6,471,637 to Green, et al., U.S. Patent Application No. 2002/0161280 by Chatenever, et al., U.S. Patent Application No. 2004/0210105 by Hale, et al., and U.S. Patent Application No. 2005/0228230 by Schara, et al.
The basic known designs of gravity-leveled endoscopic systems are illustrated in FIGS. 1A-C. FIG. 1A shows an endoscope that has an integrated shaft 10 and camera head 12. In addition to an image sensor 14, the camera head 12 also houses a processor 16 and rotation sensor 18. Power and electronic communication is provided through a cable 20. The image rotation required to level the image is done electronically by a separate processor (not shown). Because this integrated camera endoscope is a single unit, it is not compatible with the traditional endoscopes and camera heads most commonly available in the operating room, and a prospective user must buy the whole system in order to obtain gravity-leveling capabilities.
FIG. 1B shows a gravity-leveled system that has a shaft 10 that is detachable from the camera head 12, which also houses a processor 16 and a rotation sensor 18. Image leveling is accomplished by physically rotating an image sensor 14 with a motor 22 and gear train 24, 26. A disadvantage of this system is that the camera head 12 is not compatible with the standard eyepiece of traditional endoscopes, but rather, requires a special coupling between the camera head and the endoscope shaft.
FIG. 1C illustrates a camera head 12 with an eyepiece coupler 30 and pendulum 28, which seeks the upright camera position by the nature of its weight. While compatible with a traditional endoscope with an eyepiece 32 and a light post 34, one disadvantage of this solution is that the pendulum 28 is cumbersome and becomes unresponsive as it approaches horizontal. Additionally, it requires the purchase of this specialty camera head, even if a traditional camera head is already available. Finally, these systems typically do not provide gravity-leveling for rigid endoscopes with an off-axis view vector.
What is desired, therefore, is a system for orienting the images obtained by a scope independently of the orientation of the scope. What is further desired is a system for orienting the images obtained by a scope that can be employed with standard camera heads and scopes. What is also desired is a system for orienting the images obtained by a scope that is accurate, not cumbersome, and can be used with scopes having an off-axis view vector.